What polling day holds for David Butler, the co-inventor of the swingometer and the authority on post-war British elections.

Elections are an artform which people see in different ways. I'm fascinated by elections and I must say that I have not been bored by this campaign.

The swingometer

First outing in 1955

Refined by David Butler and Robert McKenzie

Initially a cardboard arrow-and-arc, propped on a desk

2001 model uses computer-generated figures and lasers

I'll spend today topping and tailing a lot of letters that I'll send out on Saturday as part of my research, congratulating people and asking questions about their campaign.

I'll vote myself, and then I shall spend the next 24 hours taking part in the commentary on the results.

'Graphic gizmos'

I was, in a sense, the Peter Snow of the BBC's election coverage on television from 1950 to 1979.

The swingometer, circa 1970

The very first swingometer was done by a man called Peter Milne, who was working on the 1955 election and commenting on the results in the south-west.

I thought it a very good idea, and persuaded the BBC to construct a more elaborate thing than his little model. So in 1959, I stood up in front of this very crude mechanical swingometer, one of many graphic gizmos used on the night.

In 1964, Bob McKenzie took over the swingometer - he loved it.

During the Greater London Council election in 1967, the swing was greater than the BBC had allowed for, and the scene-shifters spotted him painting on an extra bit.

Election night 1959 with David Butler, left

Thereafter, it became his signature and he made it good entertainment.

Stately progress

Elections have been transformed in the past half-century.

One of the advantages of being old is that one can compare things with some certainty that one knows what it was like and what it is like.

Stately event: Clement Atlee canvassing in 1950

The real turning point came in 1959, with the coming of television and opinion polls. We've now moved to 24-hour electioneering from stately middle-of-the-day events.

A simple contrast is 1950, with Atlee being driven around by his wife in an old pre-war car with just one detective with him. Churchill would go out magnificently by special train to rallies around the country.

And that was the story - the leaders gave one big speech a day at local meetings, and did it early enough to catch the newspapers' deadline.

Performance art

I think the new techniques have made elections duller, as these very professional politicians have their very professional response to every aggressive question put to them by the Paxmans and Humphrys of this world.

From Blue Peter-ish beginnings, to hi-tech tool

They know that they must keep their cool, and they know that they must give a graceful answer. And they know they must evade some questions, which are no-win questions where there's no right answer.

But if you look at it as an artform, you find yourself appreciating the skill with which the party spokesmen decide which questions to give a straight answer to and which to equivocate about because they don't want to give away any hostages of fortune.

Spectator from the sofa

During past campaigns, I used to travel around every part of the country, talking to as many officials and attending as many meetings as I could.

David Butler: "Elections are an artform"

But nowadays, without feeling I'm being idle, I can sit comfortably on my sofa and watch the telly. I recently got a dish, and can see all the press conferences live and get far more detail than in the ordinary news bulletins.

But I did spend four days on the road, talking to agents and canvassers - and being reminded how much more the election meant to me than the majority of my fellow citizens.

Am I looking forward to the next election? Oh, yes. I've come to an age where one has to be modest about looking forward.

But I'm fortunate so far in health and I can't imagine a time when I shan't be excited by elections.

David Butler, of Nuffield College, Oxford, has studied each election since 1945.